1. Field of the Invention.
The present invention relates to a tool indexing device and, more particularly, to a device for indexing gang drilling operations in cabinet panels.
2. Description of the Prior Art.
Tool indexing devices are well known in the prior art and generally function to position or align a workpiece with a tool. For example, a pilot hole borer for gang drilling precisely located pilot holes in cabinet doors for cabinet hinge mounting screws is shown in the Strange, et al. U.S. Pat. No. 4,061,437. Strange et al. disclose extensible and retractable indexing pins for precisely positioning a cabinet door on a vertical fence. A multiple drill assembly is mounted on the other side of the fence and is pneumatically actuated by an operator to extend the drill bits of the drill assembly through the fence and into a cabinet door and to retract the drill assembly when the gang drilling operation is completed.
Gang or multiple drills are also well known in the prior art and various types have heretofore been developed to suit the requirements of particular applications. A common type of gang drill includes a drill mechanism vertically movably mounted over a support for a workpiece. A plurality of tools such as twist drills and the like project downwardly from the drill mechanism and are positioned in evenly spaced, linearly aligned relation. The tools are received in respective spindles which are typically driven by a common motor. For example, the Richards U.S. Pat. No. 452,053 shows a main drive shaft with worm gears adapted for engaging worm wheels on vertical crank shaft operably connected to the drill spindles in a machine for multiple drilling heavy boiler plate. The multiple drill spindles disclosed in the Morton U.S. Pat. No. 1,265,238 are operably interconnected with each other and with a common motor by a system of drive and idler gears. Yet another type of gang drill drive system is shown in the Hill U.S. Pat. No. 1,329,663 wherein chain-driven sprockets are provided.
Gang drills are used where repetitious drilling of holes with consistent spacing and/or depth is required. One such application is in the manufacture of cabinets with adjustable shelving. Many types of cabinets include internal shelves which are vertically adjustable so that objects of various heights can be accommodated. The shelves may be supported by dowel rods or specifically designed supports including pins which are placed in receivers in the cabinet ends and dividers. Each shelf generally rests on a pair of supports at each end thereof and possibly additional supports in mid-span. By providing a plurality of vertically spaced receivers in a pair of columns on each cabinet end and divider, a corresponding set of four or more receivers may be selected for supporting a shelf fairly close to any desired position within the cabinet. Preferably the sets of corresponding receivers are horizontally coplanar so that the shelves will be level when installed.
Gang drills are well adapted for multiple drilling the cabinet ends and dividers with columns of shelf support clip receivers. For example, gang drills designed for this purpose are available from Ritter Manufacturing located in Antioch, Calif. The Ritter gang drills utilize holddowns for securing the workpiece to a platform during drilling operations. However, heretofore there has not been available a tool indexing device particularly suitable for multiple drilling shelf support recievers in cabinet ends and dividers. Many cabinets are constructed with cabinet ends and dividers of different sizes which necessitate calculating receiver placement and workpiece alignment separately for cabinet ends and dividers. Alignment for multiple drilling of cabinet ends and dividers is further complicated by the different thicknesses of materials which are commonly employed in cabinet making, since the material thickness will effect the placement of the shelf support receivers even in cabinets which are otherwise identical.
In using many prior art multiple drills, including the Ritter models, the operator had to manually align each workpiece on the drill platform before initiating the drilling operation. Manual alignment of cabinet ends and dividers on prior art gang drills tends to be relatively inaccurate and time-consuming. Furthermore, it is relatively easy for the operator to make a mistake manually aligning a cabinet end or divider. The resulting misaligned receivers may either ruin the workpiece or necessitate its redrilling. If the misalignment is not discovered until the cabinet is assembled, replacement or redrilling of the defective cabinet end or divider may be particularly difficult or time-consuming.